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Fault Model (fault + model)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Interactive editing of digital fault models

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 12 2010
Jordan Van Aalsburg
Abstract We describe an application to interactively create and manipulate digital fault maps, either by tracing existing (paper) fault maps created from geological surveys, or by directly observing fault expressions and earthquake hypocenters in remote sensing data such as high-resolution (,100k × 100k elevation postings) digital elevation models with draped color imagery. Such fault maps serve as input data to finite-element-method simulations of fault interactions, and are crucial to understand regional tectonic processes causing earthquakes, and have tentatively been used to forecast future seismic events or to predict the shaking from likely future earthquakes. This fault editor is designed for immersive virtual reality environments such as CAVEs, and presents users with visualizations of scanned 2D fault maps and textured 3D terrain models, and a set of 3D editing tools to create or manipulate faults. We close with a case study performed by one of our geologist co-authors (Yikilmaz), which evaluates the use of our fault editor in creating a detailed digital fault model of the North Anatolian Fault in Turkey, one of the largest, seismically active strike-slip faults in the world. Yikilmaz, who was directly involved in program development, used our fault editor both in a CAVE and on a desktop computer, and compares it to the industry-standard software package ArcGIS. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Seismic reflection coefficients of faults at low frequencies: a model study

GEOPHYSICAL PROSPECTING, Issue 3 2008
Joost Van Der Neut
ABSTRACT We use linear slip theory to evaluate seismic reflections at non-welded interfaces, such as faults or fractures, sandwiched between general anisotropic media and show that at low frequencies the real parts of the reflection coefficients can be approximated by the responses of equivalent welded interfaces, whereas the imaginary parts can be related directly to the interface compliances. The imaginary parts of low frequency seismic reflection coefficients at fault zones can be used to estimate the interface compliances, which can be related to fault properties upon using a fault model. At normal incidence the expressions uncouple and the complex-valued P-wave reflection coefficient can be related linearly to the normal compliance. As the normal compliance is highly sensitive to the infill of the interface, it can be used for gas/fluid identification in the fault plane. Alternatively, the tangential compliance of a fault can be estimated from the complex-valued S-wave reflection coefficient. The tangential compliance can provide information on the crack density in a fault zone. Coupling compliances can be identified and quantified by the observation of PS conversion at normal incidence, with a comparable linear relationship. [source]

Robust adaptive output-feedback control for a class of nonlinear systems with time-varying actuator faults

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 9 2010
Zhengqiang Zhang
Abstract A robust adaptive output-feedback control scheme is proposed for a class of nonlinear systems with unknown time-varying actuator faults. Additional unmodelled terms in the actuator fault model are considered. A new linearly parameterized model is proposed. The boundedness of all the closed-loop signals is established. The desired control performance of the closed-loop system is guaranteed by appropriately choosing the design parameters. The properties of the proposed control algorithm are demonstrated by two simulation examples. Copyright © 2010 John Wiley & Sons, Ltd. [source]

LMI approach to reliable guaranteed cost control with multiple criteria constraints: The actuator faults case

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 8 2009
Dengfeng Zhang
Abstract Based on the multi-objective optimization strategy and linear matrix inequality approach, the problem of reliable guaranteed cost control with multiple criteria constraints is investigated for a class of uncertain discrete-time systems subject to actuator faults. A fault model in actuators, which considers outage or partial degradation in independent actuators, is adopted. The quadratic stability is proved to be independent of the disturbance and the upper bound of a quadratic cost index is improved. The reliable feedback controller is designed to minimize the upper bound of the quadratic cost index, place all the closed-loop poles in a specified disk, constrain the H, norm level of the disturbance attenuation into a given range and guarantee the magnitudes of control inputs less than the given bound, as well. Thus, the resulting closed-loop system can provide satisfactory stability, transient behavior, disturbance rejection level and optimized upper bound of the quadratic cost performance despite possible actuator faults. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Reliability Analysis of a Novel Pulse Code Modulation Flow Control Valve with Self-compensating Ability

QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 4 2007
Zhang Peng
Abstract In this paper a self-compensating pulse code modulation compound flow control valve and its self-compensating algorithm are introduced. After adopting a self-compensating method, the compound valve can maintain good control quality when one or more turn on/off valves (TOVs) fail by adjusting the activities of unfailed TOVs. A stochastic fault model for the compound valve is established and a Monte Carlo approach is used to calculate its life distribution. The results indicate that there is about 20,50% increase of mean controllable life. This might be of great importance when immediate emergency shutdown is not allowable or too costly, such as in the case of aircraft control and in the control of continuous processes. The extra life can leave a large enough time margin to plan a more graceful shutdown and maintenance. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Inferring planar disorder in close-packed structures via,-machine spectral reconstruction theory: structure and intrinsic computation in zinc sulfide

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2007
D. P. Varn
We apply ,-machine spectral reconstruction theory to analyze structure and disorder in four previously published zinc sulfide diffraction spectra and contrast the results with the most common alternative theory, the fault model. In each case we find that the reconstructed ,-machine provides a more comprehensive and detailed understanding of the stacking structure, often detecting stacking structures not previously found. Using the ,-machines reconstructed for each spectrum, we calculate a number of physical parameters , such as configurational energies, configurational entropies and hexagonality , and several quantities , including statistical complexity and excess entropy , that describe the intrinsic computational properties of the stacking structures. [source]